IMHO, the post-processing (PP) of these pix is not extraordinary and is not even close to being the major contribution to their look and feel. The "look" that I think you are interested in is, IMHO, primarily due to careful choice of background and lighting, which, together with a decent camera/lens produces a nice, sophisticated effect.
Note that in all three photos, the background is either completely grayscale (photo #2), or strongly desaturated (in the case of photos #1 and #3). In addition, in the 1st and 3rd photos, the model also is in clothing almost devoid of color. In all three cases, the lighting is moderately diffuse and is coming in from the right, ie, almost exactly perpendicular to the camera's viewing direction. This is important to add some drama to these images. It's a lighting effect that beginning photographers almost never use.
WRT PP, the one thing that I would note is that the white balance is done very precisely to preserve the quasi-monochrome look, and great care was obviously taken to ensure the skin colors were good. Other than possibly a bit of "curves" to darken some of the shadow areas, I doubt much else was done to these in PS.
HTH,
Tom M